docs: def norm(self):
          """
          Efficient computation of the Frobenius norm for ktensors
  
          Returns
          -------
          norm : float
              Frobenius norm of the ktensor
          """
          N = len(self.shape)
          coef = outer(self.lmbda, self.lmbda)
          for i in range(N):
              coef = coef * dot(self.U[i].T, self.U[i])
          return np.sqrt(coef.sum())